Implementation of Wider Lane Lines to Improve Sight Distance from Opposing Left-Turn Lanes

Vehicles turning left at intersections from opposing left-turn lanes often restrict each other’s sight distance. Previous research has developed guidelines for offsetting opposing left-turn lanes to provide adequate sight distances. Implementation of these guidelines at existing intersections typically involves reconstructing the left-turn lanes. However, the results of the before-and-after studies presented demonstrate that increasing the width of the lane lines between left-turn lanes and the adjacent through lanes also can be used as a means of improving the sight distance between opposing left-turn lanes. Regression analysis was used to determine a relationship between lane-line width and available sight distance that can be used to design lane-line widths that provide the required sight distance for opposing left-turn vehicles.